This invention relates to an engine driven arc welder, especially to an engine-driven arc welder which may be adjusted in accordance with the characteristics the type of sheathed electrode or the welding position.
Engine driven arc welders weld by creating an arc between the electrode and the material being welded. The power for this comes from a generator driven by an engine, and this power is controlled by a controlling signal and controlling elements.
In arc welding, short-circuits often occur when molten metal or the electrode comes into direct contact with the material being welded. When the welder (operator) goes to re-start the arc after such a short-circuit, if the welder (apparatus) is such that it produces a large current the arc will be easy to re-start, though much sputtering will be produced. On the other hand, if the welder of the type that does not produce a large current in order to ensure better welding quality, it will be difficult to re-start the arc after shorting. This results in the arc cut-off or the electrode sticking the base material. Thus, the welding work may be interrupted if the welder is not so skillful. These kinds of problems are likely to occur particularly when work is carried out in areas where the current is low or when the arc is short.
In the conventional welders in which large current flows during a short-circuit, the arcing can be interrupted the electrode may stick to the base metal and electrode and much spattering may occur, depending on the type of electrode used and the welding position. This is because the characteristic voltage during a transition from a constant current characteristic to an increased current characteristic and the increased fixed current characteristic value for a short circuit are fixed in advance to suit the type of electrodes used in Japan. Even in the case a skilled welder carries out the welding, the appearance of the beads will be less than satisfactory and fine adjustments to the manipulation of the electrode are difficult to carry out, if much sputtering occurs. In addition, when welding is carried out using high cellulose type electrodes, as is often used in overseas countries, it becomes even more difficult to deal with such problems.